A refrigeration system such as an air conditioning system is equipped with various devices such as a compressor and a fan. Motors are often used as the drive sources of these devices. The motors are driven by power supplied from a commercial power supply (hereinafter referred to simply as power).
In this connection, there are cases where, for example, a high pressure abnormality occurs in the compressor. A high pressure abnormality is a phenomenon where the pressure of the refrigerant after being compressed by the compressor ends up falling outside the normal pressure range for some reason relating to the compressor, resulting in a high pressure state in which the pressure of the refrigerant is higher than a predetermined value on the high pressure side of the range.
To address this, a technology which, in a case where a high pressure abnormality has occurred, cuts off the supply of power to the motors to thereby stop the operation of the refrigeration system is known, as described in Japanese Patent No. 4,738,129.